1. Field of the invention
The present invention relates to a novel .alpha.-glycosyl derivative of a catecholamine or its salt (the wording ".alpha.-glycosyl derivative of a catecholamine or its salt" will be designated as ".alpha.-glycosyl catecholamine" hereinafter, if specified otherwise), and to its preparation and uses, more particularly, to an .alpha.-glycosyl catecholamine which does not substantially exhibit a reducing activity and turns green on the anthrone-sulfuric acid method, and to a process for preparing an .alpha.-glycosyl catecholamine, as well as to its uses, said process comprising allowing a saccharide-transferring enzyme to act on a solution containing an .alpha.-glycosyl saccharide and one of catecholamines and their salts (the wording "catecholamines and their salts" will be designated as "catecholamines" hereinafter, if specified otherwise) in order to form an .alpha.-glycosyl catecholamine, and recovering the resultant .alpha.-glycosyl catecholamine.
2. Description of the prior art
As described in publications such as The New England Journal of Medicine, Vol. 280, No 7, pp. 337-345 (1969); Proceedings of the National Academy of Sciences of the United States of America, No. 69, No. 8, pp. 2145-2149 (1972); and Seikagaku-Jikken Koza, titled "Metabolism of amino acids, and in vivo amines", Part B, Vol. 11, pp. 725-753 (1977), edited by The Japanese Biochemical Society, published by Tokyo-Kagaku-Dozin Co., Ltd., Tokyo, Japan, catecholamines are one of biologically-active amines, and have been known as a compound which exhibits a variety of pharmacological activities, and because of these they have been used as an anti-Parkinson's disease agent or anti-parkinsonism agent, mydriatic, hypotensor, antitussive, expectorant, adrenal medullary hormone, vasohypertonic and cordial, as well as an agent for autonomic nerve.
Although the catecholamines have a reducing activity and a relatively-high stability in an aqueous acid solution, they are readily oxidized under atmospheric conditions to change their colors and to form sediments, and because of these their actual uses are inevitably highly restricted. They also have a drawback, i.e. they have a phenolic hydroxyl group which allows them to be conjugated, methylated and oxidized in a relatively-high level when orally administered and passed through gastrointestinal walls.
As described in Insect Biochemistry, Vol. 14, No. 5, pp. 487-489 (1984) and Comparative Biochemistry and Physiology, Part B, Comparative Biochemistry, Vol. 97B, No. 3, pp. 563-567 (1990), glycosylated catecholamines are found in natural compounds in a .beta.-glucosylated form, but have not yet been artificially synthesized via an enzymatic technique, and the industrial-scale preparation has been deemed difficult.
It has been a great demand to overcome drawbacks of conventional catecholamines, and to establish a novel catecholamine derivative which exerts a satisfiable physiological activity in vivo without a fear of causing undesirable side-effects.